US6442355B2ExpiredUtilityA1

Developer density controlling apparatus including target density information detection and toner image density detection

Assignee: CANON KKPriority: Feb 24, 1999Filed: Feb 23, 2000Granted: Aug 27, 2002

Est. expiryFeb 24, 2019(expired)· nominal 20-yr term from priority

Inventors:Kazuhiro Hasegawa Shigeo Kimura Koji Masuda Akihiko Sato Takao Ogata Fumitake Hirobe

G03G 15/0855G03G 15/5041G03G 2215/00042

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Claims

Abstract

A developer density controlling apparatus includes image density detecting device for detecting a target density on the basis of a detected image and, if a difference between a toner density detected by a developer density detecting device and the target density is equal to or greater than a predetermined value, the image density detecting device does not correct the target density.

Claims

exact text as granted — not AI-modified

What is claimed is:

1. A developer density controlling apparatus comprising:
first detecting means for detecting information corresponding to a density of a toner in a developer in a developer container;
second detecting means for detecting information corresponding to a density of a toner image; and
control means for controlling a replenishing amount of the toner with which said developer container is replenished on the basis of an output of said first detecting means and a target value;
wherein said apparatus includes a first mode for changing the target value in accordance with the output of said first detecting means and an output of said second detecting means, and a second mode for not changing the target value in accordance with the output of said first detecting means and the output of said second detecting means,
wherein a number of an image forming operations effected between a detecting operation and next detecting operation, which are effected by said second detecting means, is larger in the second mode than in the first mode.

2. A developer density controlling apparatus according to claim 1 , wherein, in case of said first mode, said control means controls the replenishing amount of the toner by using the target value changed in accordance with the output of said first detecting means and the output of said second detecting means.

3. A developer density controlling apparatus according to claim 2 , wherein said control means controls the replenishing amount of the toner on the basis of a difference between the output value of said first detecting means and the target value changed in accordance with the output of said second detecting means.

4. A developer density controlling apparatus according to any one of claims 1 to 3 , wherein, in the case of said second mode, said control means controls the replenishing amount of the toner by using a last target value.

5. A developer density controlling apparatus according to claim 4 , wherein said control means controls the replenishing amount of the toner on the basis of a difference between the output value of said first detecting means and the last target value.

6. A developer density controlling apparatus according to claim 1 , wherein said first detecting means detects the information corresponding to a density of the developer by receiving a reflected light from the developer irradiated by a light.

7. A developer density controlling apparatus according to claim 1 , wherein said second detecting means detects information corresponding to a density of a developer image for detection formed on an image bearing member.

8. A developer density controlling apparatus according to claim 7 , wherein said second detecting means detects the information corresponding to the density of the developer image for detection by receiving a reflected light from the developer image for detection which is irradiated by a light.

9. A developer density controlling apparatus according to claim 1 , wherein the developer includes a carrier.

10. An image forming apparatus comprising:
first detecting means for detecting information corresponding to a density of a toner in a developer in a developer container;
second detecting means for detecting information corresponding to a density of a toner image; and
control means for controlling a replenishing amount of the toner with which said developer container is replenished on the basis of an output of said first detecting means and a target value;
wherein said apparatus includes a first mode for changing the target value in accordance with the output of said first detecting means and an output of said second detecting means, and a second mode not for changing the target value in accordance with the output of said first detecting means and the output of said second detecting means,
wherein a number of an image forming operations effected between a detecting operation and next detecting operation, which are effected by said second detecting means, is larger in the second mode than in the first mode.

11. A developer density controlling apparatus according to claim 10 , wherein, in the case of said first mode, said control means controls the replenishing amount of the toner by using the target value changed in accordance with the output of said first detecting means and the output of said second detecting means.

12. A developer density controlling apparatus according to claim 11 , wherein said control means controls the replenishing amount of the toner on the basis of a difference between the output value of said first detecting means and the target value changed in accordance with the output of said second detecting means.

13. A developer density controlling apparatus according to any one of claims 10 to 12 , wherein, in the case of said second mode, said control means controls the replenishing amount of the toner by using a last target value.

14. A developer density controlling apparatus according to claim 13 , wherein said control means controls the replenishing amount of the toner on the basis of a difference between the output value of said first detecting means and the last target value.

15. A developer density controlling apparatus according to claim 10 , wherein said first detecting means detects the information corresponding to a density of the developer by receiving a reflected light from the developer which is irradiated by a light.

16. A developer density controlling apparatus according to claim 10 , wherein said second detecting means detects information corresponding to a density of a developer image for detection formed on an image bearing member.

17. A developer density controlling apparatus according to claim 16 , wherein said second detecting means detects the information corresponding to the density of the developer image for detection by receiving a reflected light from the developer image for detection which is irradiated by a light.

18. A developer density controlling apparatus according to claim 10 , wherein the developer includes a carrier.

19. A developer density controlling apparatus comprising:
first detecting means for detecting information corresponding to a density of a toner in a developer in a developer container;
second detecting means for detecting information corresponding to a density of a toner image;
control means for controlling an amount of the toner replenished to said developer container based on an output of said first detecting means and a target value;
change means for changing the target value in accordance with an output of said second detecting means; and
determining means for determining whether the target value is changed by said change means in accordance with the output of said first detecting means,
wherein a number of an image forming operations from when the target value is changed to when the target value is next changed is capable of being changed.

20. A developer density controlling apparatus according to claim 19 , wherein said determining means does not change the target value if a difference between the output of said first detecting means and the target value is not less than a predetermined value.

21. A developer density controlling apparatus according to claim 20 , wherein the amount of the toner replenished is controlled based on a difference between the output of said first detecting means and last target value.

22. A developer density controlling apparatus according to claim 19 , wherein said determining means changes the target value if a difference between the output of said first detecting means and the target value is less than a predetermined value.

23. A developer density controlling apparatus according to claim 21 , wherein said control means controls the amount of the toner replenished based on a difference between the output of said first detecting means and the target value after being changed by said change means.

24. A developer density controlling apparatus according to claim 19 , wherein said first detecting means detects the information corresponding to the density of the developer by receiving a reflected light from the developer irradiated by a light.

25. A developer density controlling apparatus according to claim 19 , wherein said second detecting means detects the information corresponding to the density of the developer image for detection, which is formed on an image bearing member.

26. A developer density controlling apparatus according to claim 25 , wherein said second detecting means detects the information corresponding to the density of the developer image for detection by receiving a reflected light from the developer image for detection irradiated by a light.

27. A developer density controlling apparatus according to claim 19 , wherein the developer includes a carrier.

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